HU221091B1 - Process for the desulfurization of sulfurous acid gas-containing waste gas - Google Patents

Abstract

The present invention relates to a process for desulfurizing waste gases containing sulfur dioxide by contact with an absorbent liquid. The waste gases are desulfurized by blowing them into a stirred absorber liquid (L) filled into a reactor vessel until a certain liquid level is reached through a plurality of gas distribution pipes (7) extending vertically downwards from a space separating plate (3, 14) has a plurality of holes (8) in the lateral circumference of the pipe wall for gas injection, during which said waste gases contact the sulfur with the absorption liquid (L) and the desulfurized gases enter the upper space (B) between said partition plate (3, 14) and the respective liquid level ). The method according to the invention is characterized in that - the holes for the gas injection are arranged horizontally one after the other in the gas distribution pipes; - for the distance P between the centers of two adjacent holes serving each gas supply target, the relation 1.15? P / D? 6 is valid, where D is the smaller hole diameter; - the waste gases are Vmax. flow through the holes at maximum speed to be met - Y? 4,5S; - Y? 24 S; - a 0.05? Y? 1.0; and - the conditions of 0.005? S? 0.06, where Ya is the pressure required to desulfurize the waste gas and S is the pressure Vmax at the holes. the quotient of the throttling pressure of the waste gas blown through the flow rate and the density of the absorption fluid; - the gas distribution pipes are arranged in such a way that the relation LI? S / 10.0 is valid for the minimum distance LI between adjacent pipes, where S is already given; and - the holes are located in the gas distribution pipes in such a way that the average distance LII between the level of the liquid in the absorption fluid measured when the gas injection is stopped and the center of each hole for gas injection is given, where S is already given. The process according to the invention makes it possible to desulfurize waste gases at lower cost and more safely than with previously known processes. ŕ

Description

SUMMARY OF THE INVENTION The present invention relates to a process for desulfurizing waste gases containing sulfur dioxide by contacting them with absorbent fluids.

A desulphurisation process is known in which waste gas containing sulfur dioxide is injected into an absorbent liquid filled with a reactor vessel through a plurality of gas distribution tubes (spray roses) extending vertically downward from the space divider into the absorbent liquid. In the lower part of these gas distribution pipes, there are numerous holes in the wall of the tube for injecting the gas. Upon contact of the waste gas with the absorbent liquid, the sulfur is released and the desulfurized gas enters the upper space between the separating plate and the level of the absorbent liquid and then exits the reactor vessel (JP-B 3-70532 and JP-A 3-72913). publication documents).

However, the known process has a number of disadvantages: relatively high running costs, high investment in the process, and the inability to maintain a stable operation over a long period of time.

Thus, the main aim of the present invention has been to develop a process for reliably desulfurizing waste gases containing sulfur dioxide at low operating costs.

SUMMARY OF THE INVENTION This object is achieved by a process according to the present invention for desulphurizing sulfur dioxide containing waste gases by introducing them into a reactor vessel to a mixed volume of absorbent liquid up to a certain level of liquid 40 through a plurality of gas distributor plates extending vertically downwardly into said absorber fluid and having a plurality of holes in its lower portion, sideways circumferentially in the wall of the tube, for gas inlet, wherein said waste gases release sulfur in contact with said absorber fluid, and they enter the upper space between a given fluid level, characterized in that

the gas supply holes in each of said gas distribution pipes are substantially horizontal in series;

- in each of said gas distributor pipes, each of said two adjacent gas inlet holes is spaced so that, if each of said two gas inlet holes is considered to be a circle having the same area as the gas inlet, , is valid for the distance P between the centers of two adjacent holes

1.15 <P / D <6, where D is the diameter of the smaller of the two circles;

- passing said waste gases through each of said gas inlet holes at a maximum velocity V _max such that

Y <4.5 S;

Y <24 S;

- a 0.05 <Y <1.0; and

- the <.005 S <.06 conditions where pressure Y of the waste gas required for desulfurization and S of the gas injection hole of the said maximum speed V _max purged waste torlónyomásának said gas absorbing liquid and the specific density of the quotient;

- the gas distribution tubes are arranged such that the minimum distance L, between the two adjacent gas distribution tubes, is equal to the ratio 1,5 <L, / S <10,0, where S is as defined above; and

- said gas supply holes are located in each of said gas distribution pipes such that the average level Ln of said absorbent liquid, measured at the time of gas supply interruption, and the center of each said gas supply hole, is

2 <L „/ S <20 where S is as defined above.

Brief description of the drawings

Various important information, features, and advantages of the practice of the present invention will now be described by reference to preferred embodiments of the invention. The following drawings illustrate the description:

Fig. 1 is a side elevational view of an embodiment of a desulphurisation apparatus for carrying out the process of the present invention;

Figure 2 is a schematic side view of one of the locations of the gas inlet holes on the gas distributor pipe;

Figure 3 is a view similar to Figure 2 showing a schematic side view of a gas distribution hole for a gas supply pipe;

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Figure 4 is a schematic side view, similar to Figure 1, of a cross-sectional view of another embodiment of a desulphurisation apparatus for carrying out the process of the present invention; and

Figure 5 is a diagram showing the relationship between the waste gas pressure required for desulphurisation and the value S.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS OF THE INVENTION

Figure 1 shows one of the desulphurisation apparatuses for carrying out the process of the invention, hereinafter referred to as apparatus 1. The first partition plate 3 and the second partition plate 14 are located inside the jacket part 2 of the device 1. These divider plates divide the space within the mantle portion into three chambers, the first being the bottom chamber 4, the second the center chamber 5, and the third the top chamber 15. The partition plate 3 and the partition plate 14 can each be a horizontal plate or a gradient or inclined inclined plate. Generally, the baffle plate 14 is inclined.

The first chamber, i.e. chamber 4, contains a certain amount of absorbing fluid L. Above the liquid level LS of the absorbing liquid L is the upper space B.

The gas inlet 6 of the second chamber, i.e. the chamber 5, serves to introduce the waste gas to be treated into the chamber 5. A plurality of gas distribution tubes 7 (spray roses) are attached to the partition plate 3 and these tubes extend vertically downwardly into the first chamber, i.e. chamber 4, so that the waste gas introduced into the second chamber, i.e. chamber 5, is disposed on the gas distributor pipes 7. through which it can be injected into the absorber liquid L. Each of the gas distribution pipes 7 has a plurality of horizontally spaced holes 8 for supplying gas in the bottom wall of the pipes.

In Fig. 1, W denotes the measurable liquid level of the absorptive liquid L in the event of a gas supply interruption through the gas distribution pipes 7. The gas supply holes 8 are located below the liquid level W. Thus, a mixed-phase layer, i.e. gas and liquid, is formed on the surface of the absorbent liquid when the waste gas fed into the gas distribution pipes 7 is drawn into the absorbent liquid through the holes 8 for supplying the gas. The sulfur dioxide in the waste gas is absorbed in this L / A gas / liquid phase layer. During contact with the absorbing liquid L, the desulfurized waste gas then flows into the upper space B above the liquid level LS. The absorbent liquid L may be an aqueous gypsum slurry containing an absorbent such as a calcium compound such as limestone or slaked lime.

The first chamber, i.e. chamber 4, and the third chamber, i.e. chamber 15, are connected by one or more risers 16. At the top of the third chamber, i.e. chamber 15, is a gas outlet 9. Thus, in the upper space B, the desulphurised gas flows upwards and horizontally. As the desulphurised gas flows into the upper space B, most of the mist-forming materials and solid particles contained therein are separated due to the effect of gravity and collisions with the gas distributor tubes 7. The previously desulphurized gas, thus separated from the liquid and solid particles, enters via a riser 16 into a third chamber, i.e. chamber 15, where the upward flow of gas is reversed and the gas flowing horizontally from the third chamber, i.e. chamber 15, It exits through 9 gas discharge openings.

As the desulfurized gas flows through the third chamber, i.e. chamber 15, the entrained liquid and solid particles are separated and collected on the baffle plate 14. To remove material deposited on the baffle plate 14, washing fluid, such as gypsum-containing slurry, gypsum-containing absorbent liquid, ordinary water or seawater, is fed to the third chamber, i.e. chamber 15, through which the wash fluid is discharged.

For economical operation and effective separation of mist-forming substances and solid particles, it is advantageous to have an average descending flow rate of the desulphurized gas in the upper space of 0.5-5 m / s, more preferably 0.7-4 m / s. s. The average flow rate of the ascending gas is determined from the area of the horizontal cross-section of the upper space B, but does not take into account the area of the horizontal cross-sections of the gas distribution pipes 7 and other structures which do not allow desulphurization.

The desulphurized gas in the upper space B should be flushed with an average horizontal velocity of not more than 8 m / s, more preferably not more than 6 m / s in order to form a stable mixed gas / liquid phase in layer A. The average horizontal flow rate is determined by reference to the vertical cross-section of the upper space B up to the end of the riser 16.

It is advantageous for the effective separation of mist constituents and solids, and for economical operation, that the desulphurized gas 16 flows upwardly at 6-20 m / s, more preferably 8-15 m / s.

The desulfurized gas introduced into the third chamber, i.e. chamber 15, strikes the upper wall of the chamber and has a flow direction which is horizontal. Thus, in the third chamber, i.e. chamber 15, the liquid and solid particles are separated against the wall by collision and gravity. It is advantageous for the effective separation of said particles that the average horizontal flow rate of the desulfurized gas in the third chamber is not more than 10 m / s, more preferably not more than 8 m / s. The average horizontal flow rate is given by the vertical cross-section of the third chamber which is measured 2 m horizontally from the gas outlet 9.

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The gas distribution tubes 7 may be of cross-sectional shape as desired, circular, polygonal (triangular, rectangular or hexagonal) or rectangular trough. The holes 8 for circulating gas in the sidewall of each gas distribution pipe 7 may, if desired, be of any shape: circular, triangular, rectangular, hexagonal, slit or star-shaped. As shown in Fig. 3, the blowing holes 8 may be arranged in two or more rows as desired. Preferably, the equivalent internal diameter D _{p of the} gas distribution pipes 7 is sufficient to

2D _H <D _p <12D _H , more preferably a

_DH <D _p <10D _H where D _{H is} the equivalent diameter of the 8 holes for gas injection. A _p equivalent inner diameter is generally from 25 to 300 mm, preferably 50-300 mm. The _DH equivalent diameter of the holes 8 for gas injection is usually 3 to 100 mm, preferably 5 to 50 mm.

Equivalent diameters D _p and D _h are defined as follows:

- D _p - 4Sp / L _p , where

S _{p is} the portion of the horizontal cross-section of the gas distributor pipe 7 measured inside the pipe where there are holes 8 for the supply of gas; and

- L _p inner periphery of the sparger pipe 7 to the length also at the place where there are eight holes of the gas injection; and - D _H -4 S [j / Lpj, where

- S _{H is} the "area" of the 8 holes for gas injection; and

- L _H is the length of the inner circumference of the 8 holes for gas injection.

The lower open end of all gas distributor tubes 7 may be formed as desired. For example, the lower end of these tubes may be horizontal, oblique, slotted or corrugated.

The average axial distance L _x between the center (geometric center of gravity) of the gas supply hole and the lower end of the gas distributor pipe 7 should be adjusted so that the bottom open end of the gas distributor pipe is practically free from waste gas, in other words the level of absorber liquid L should always be in the gas distributor tube 7. This can be achieved in the case where the L _x distance between 3S and 8S, preferably adjusted to the range from 4S to 7S, wherein S hole for gas injection maximum flow velocity _Vmax blown gas torlónyomásának and the absorbing liquid L the density of the quotient.

Preferably, gas cylinders are made of plastic cylinders having an internal diameter of 25 to 300 mm and having a plurality of circular holes 5 to 100 mm in diameter spaced apart.

The riser 16 may have any desired cross-sectional shape. For example, this tube may be circular, square, or rectangular triangular in cross-section.

It is important that each of the two adjacent holes 8 for the gas supply in each of the gas distribution pipes 7 is so spaced that if each of the two holes 8 for the gas supply is considered to be a circle having the same area as the hole 8 for the gas supply the distance (P) between the centers of gravity (geometric centers of gravity) of the holes is given by

1.15 <P / D <6 condition, preferably

1,2 <P / D <5 condition, where D is the diameter of the smaller of the two circles mentioned. Figures 2 and 3 show examples of arrangement of holes for gas injection.

When the P / D ratio is less than 1.15, the rate of desulphurisation is much lower, since gas streams blown through separate holes for blowing tend to merge. It is the case that the gas streams leaving the adjacent holes for blasting interferes with one another such that the mixed gas / liquid phase A (foam phase) becomes unstable. A P / D ratio of less than 1.15 is also detrimental to the manufacture and maintenance of the gas distributor pipe 7. On the other hand, if the P / D ratio is too high, that is, greater than 6, the volumetric efficiency is reduced to such an extent that, to the disadvantage, large equipment has to be used.

It is also essential that the waste gases be flown through each of the 8 holes for gas injection at a maximum flow rate V _max such that conditions (1-4) are met:

- (1): Y> 4.5 S, preferably Y> 6.5 S;

- (2): Y <24 S, preferably Y <22 S;

- (3): 0.05 <Y <1.0; and

- (4): 0.005 <S <0.06, where Y is the depressurization pressure of the waste gas and S is the quench pressure of the waste gas blown at the maximum flowrate V _max and the density of the absorbing liquid.

The pressure to desulphurize the waste gas (expressed as the height of the absorption liquid column in m) can be expressed by the following equation:

Y-T + L ', where T is the ratio of the pressure loss in kg / m ^{2 of the} gas passing through the 8 holes for gas injection and the density ρ _π of the absorbing liquid L in kg / m ³ , and L _n for the gas injection The center of gravity of the 8 holes and the mean distance of the liquid level W of the absorber liquid measured at rest, i.e. when the gas supply to the distributor tube 7 is stopped. In other words, the pressure Y is the value obtained when the pressure, expressed in kg / m ² , is required for the waste gas fed to the gas distributor pipe 7 to be

EN 221 091 Β1 through 8 holes for gas injection into the upper space B divided by the density p _{n of the} absorber L expressed in kg / m ³ .

The value of T is substantially in the range 2.5S to 4S - S is as defined above - and depends on the shape of the 8 holes for gas injection and the flow rate of the waste gas. In view of the fact that, as will be described later, the L _n / S ratio between 2 and 20 is preferably between 4 and 18, as will be described later, the pressure Y may be expressed as follows:

^Y - ^T + ^L ii, where T and L _n are as defined above,

- (number between 2.5 and 4) S + (number between 2 and 20)

- (number between 4.5 and 24.

Maximum velocity V _max and the S value have the following relationship:

S - (tensile pressure at maximum flowrate V _max ) / (density of the absorbing liquid p _n ),

- (Pi ^x Vmax. ^X V _max / 2G) / p „~ V ² max. * Pl / 2G p _n , where pi is the density of the waste gas in kg / m ³ , Pn is the density of the absorbing liquid in kg / m ³ and G is the value of gravity acceleration, ie 9,8 m / s ² .

Figure 5 illustrates the relationship between S value and pressure Y at different degrees of desulphurisation Z. "Degree of desulphurisation Z" is given herein as a percentage

ZO-based Qki / QbeblOO '/ o equation, where Q _kl of sulfur dioxide in exhaust gas through the outlet port 9 clean gas flow rate, Q _in is sulfur dioxide in the gas inlet 6 through the waste gas feed flow. Figure 5 shows that a minimum depressurization value of Y can be assigned to a given desulphurisation rate Z. It is preferable to adjust the S value so that the desired Y desulphurisation degree is minimized. For example, in order to achieve a desulphurisation rate of 90% Z, it is preferable to set the S value to about 0.017 m. However, in order to achieve a desulphurisation rate of 70% Z, it is advisable to set the S value to about 0.009 m. If, on the other hand, desulphurisation is carried out while varying the desulphurisation degree desired from 99% to 70%, it is advisable to set the S value to 0.035 m, since in this case the desulphurisation rate of 99% has a minimum Y pressure of 70%. Even with a degree of desulphurisation of%, the conditions (1) (4) already described are fulfilled. Once the S value has been determined, the maximum flow rate V _max can be calculated from the

SV ^{2 from the} max xp, / 2G p 'equation.

From the maximum flow rate V _max , it is then possible to determine the number of gas distributor pipes 7 and the total area of the openings 8 for gas injection in each gas distributor pipe 7.

There are no particular restrictions on the arrangement of the gas distribution pipes 7 connected to the partition plate 3, provided that the distance Lj between the two adjacent gas distribution pipes 7 meets the requirements of 1.5, <L, / S <10.0.

2 <Lj / S <8, where S is as defined above. Lj is the minimum distance between the outer circumference of a given gas distributor pipe 7 and the outer circumference of the gas distributor pipe 7 which is closest to the given pipe among all the gas distributor pipes 7. In the case where the Lj / S ratio is less than 1.5, the degree of desulphurisation is much lower as the gas stream ejected from the two adjacent gas distribution tubes 7 interferes with one another, thereby rendering the mixed phase gas / liquid phase A unstable. On the other hand, if the L / S ratio is too high - that is, above 10 - the volumetric efficiency is reduced and therefore large equipment must be used.

The distance Lj is usually 0.05-0.6 m, preferably 0.075-0.45 m. This distance must be set so as to meet the requirement for the Lj / S ratio already described. It is advisable to set the distance Lj as low as possible in order to handle a larger amount of waste gas per unit area of the baffle plate. The S value is calculated from the equation already described. In this regard, it is noted that V _{max has a} maximum flow rate of 8-35 m / s, a waste gas p ₍ density 0.91-1.2 kg / m ³ and a absorption liquid pn density 1,000-1,300 kg / m ³⁾ . it is desirable to keep the S value as low as possible in order to reduce the cost of operating the equipment, i.e. desulphurisation, but it should be noted that too small S values are not advantageous in terms of investment cost. By reducing the flow rate, i.e., by increasing the DH equivalent diameter of the gas supply holes or by increasing the number of gas supply holes, As mentioned above, the gas supply holes 8 have a D _H equivalent diameter of generally 3-100 mm.

It is also important that the 7 sparger are arranged in eight holes of the gas injection tubes to L _{n has} an average distance between the L elnyelőfolyadéknak measured gas is introduced into the 7 sparger tube paused W liquid level and each hole 8 of the gas injection midpoint meet

2 <L "/ S <20, preferably 4 <L" / S <18, more preferably 6 <L "/ S <16, where S is as defined above.

In the case where the L _n / S ratio is less than 2, the waste gas is not sufficiently contacted with the L absorbing liquid, so that the desulphurisation efficiency is reduced. If the L _n / S ratio exceeds 20, the gas bubbles in the waste will merge and the L

As they pass through an absorbent liquid, their size is increased to such an extent that the effectiveness of the contact between the liquid and the gas is reduced. The depth L _{n is} generally 0.05-0.9 m, preferably 0.075-0.75 m.

If the S value or the depth L _{n is} large, the waste gas Y pressure is high and the degree of desulphurisation increases. However, in this regard, it should be noted that operating costs dependent on Y pressure increase with increasing Y pressure. In the case where the Ln / S ratio is kept within the range already described, the pressure of the waste gas Y fed into the gas distribution pipes can be kept low. Thus, it is possible to save on desulphurisation energy, i.e. to reduce the cost of desulphurisation.

If the depth L _n is adjusted to satisfy the condition 4.5 S <Y <24 S already described (Figure 5) and the condition 2 <L _n / S <20, the desulphurisation Y pressure can be kept low, whatever Z desulphurisation degree is desired. For example, for the curves in Figure 5, only the desired desulphurisation degree Z changes, while other parameters such as the inside diameter of the gas manifolds, the volume flow of the waste gas per gas manifold, the pH of the absorbing liquid and the sulfur content of the waste gas -the concentration of carbon dioxide remains constant. The shape and position of each curve will vary depending on these parameters.

As mentioned above, the S value must meet the requirement of 0.005 <S <0.06. However, it is also apparent from Figure 5 that the appropriate S value varies depending on the degree of desulphurisation Z that we intend to achieve. In case the desulphurisation equipment operates under different operating conditions, it is advisable to keep the S value high enough so that the desulphurisation can be performed with low energy consumption.

The Ljj / S ratio is an important parameter for controlling desulphurisation equipment performance and is an effective means of achieving the goal of desulphurisation at a given degree of desulphurisation Z at a minimal operating cost. The depth L _n can be changed by lowering or increasing the liquid level W. The appropriate depth L _n can be adjusted by controlling the amount of absorptive fluid L in the reactor or by controlling the amount of oxidizing gas, such as air, supplied to the absorber fluid L through the conduit 12.

The absorptive fluid L must be stirred with one or more stirrers 10 to effect the desulphurisation. The mixer 10 consists of a rotating mixing shaft 10 'extending vertically or obliquely into the chamber 4 and one or more blades or propellers which are fixed to and coincident with the tip of the rotating mixing shaft 10'. In this case, it is advisable to mix the absorbent liquid with one or more agitators operated at a total power of 0.05-0.2 W, preferably 0.08-0.15 W per cubic meter, in order to achieve a very stable level of desulphurisation.

It is expedient to carry out the stirring so as to form a main stream of recirculation in the stirred absorbent liquid L. The main recirculation current is represented by the arrow R in Figure 1. The main current is accompanied by random currents. Referring to Figure 1, reference numeral 11 denotes an atomiser feed line with an injector, from which the absorbent is injected into the mainstream recirculation stream R. The absorbent is rapidly dispersed in the absorbent liquid L and reaches the mixed phase A gas and liquid layer A in a short period of time. If necessary, the absorbent can be fed through a plurality of conduits 11. It is desirable to feed the absorbent into the mainstream recirculation stream R where the impeller 10 creates an upward or downward flow.

The diameter of the nebulizer for injecting the absorbent is usually 20 to 100 mm, preferably 25 to 75 mm. It is advisable to use multiple nebulizers to rapidly distribute the absorbent in the absorbent fluid L and prevent local increases in pH and material deposition on the walls of the gas distribution tubes. It is expedient to use a nebulizer based on 20-500 m ³ , preferably 30-300 m ^3, of the L absorbing liquid. The absorbent is injected at a mass flow rate of from 0.5 to 20 kgmol / h, preferably from 1 to 10 kgmol / h.

A portion of the absorber fluid L is removed from the chamber 4 via the conduit 13 to maintain the gypsum content of the absorber fluid L below a predetermined level. If necessary, a portion of the drained fluid may be treated to remove the gypsum, and then the gypsum-free liquid may be mixed with the absorbent and returned through the conduit 11 to the first chamber, i.e. chamber 4. In order to prevent pH increase in the zones adjacent to the 8 holes for gas injection, it is advisable to maintain the amount of absorbent in the recirculating absorbent liquid such that the amount of gypsum (CaSO ₄ x 2H ₂ O) and absorber M 1-20, preferably 1-10, so that no fine gypsum crystals or fine calcium carbonate crystals are precipitated or, if fine crystals are formed, become large crystalline particles so as to prevent blocking holes and / or deposits on the wall of the gas distributor pipe 7.

If necessary, a portion of the absorbing liquid L can be recycled and sprayed into the chamber 5 for cooling and washing the same feed gas.

It is desirable to inject the aforementioned oxidant gas, fed through the conduit 12, into the mainstream recirculation stream R where the downward flow of the agitator blade 10 is generated. In the mixed phase A containing gas and liquid, the following reaction occurs when the waste gas is trapped in the form of gypsum sulfur dioxide:

SO ₂ + CaCO ₃ + l / 2 O ₂ + H ₂ O -> CaSO ₄ lx2H ₂ O + CO ₂ 1 \

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In order to increase the degree of desulphurisation Z, it is necessary for this reaction to be carried out efficiently in the mixed phase A gas and liquid. It is expedient to introduce the oxidizing gas into the absorbing liquid L in such a manner that the molar ratio of oxygen to oxygen in the oxidizing gas to sulfur dioxide in the waste gas is 0.5 to 6, preferably 1 to 5.

Figure 4 shows a desulphurisation apparatus according to another embodiment of the process of the invention. Similar structural units are designated in Figure 1 and Figure 4 by the same reference numerals. The interior of the jacket portion 2 of the apparatus shown in FIG. 4 is divided into two parts by the partition plate 3: the first, lower chamber 4, and the second, upper chamber 5. The first chamber, i.e. chamber 4, contains a certain amount of absorbing fluid L, which is located above the liquid level LS in the upper space B. The waste gas to be treated is fed through the second chamber, i.e. the gas inlet 6 of the chamber 5, and through a plurality of gas distribution holes 8 arranged in series on the underside of each of the gas distribution tubes 7 and injection into the absorptive fluid L.

Upon contact with the absorbing liquid L, the desulphurized waste gas then flows into the upper space B above the liquid level LS. The average flow rate of the desulphurized ascending gas in the upper space B is preferably 0.5-5 m / s, more preferably 0.7-4 m / s, while the horizontal average flow rate of the desulphurized gas in the upper space B is preferably not more than 8 m / s, more preferably up to 6 m / s. As the desulfurized gas flows into the upper space B, most of the mist-forming materials and solid particles contained therein are separated by the force of gravity and collisions with the gas distributor tubes 7. The previously desulphurized gas, previously liberated from said liquid and solid particles, is discharged through the gas outlet 9.

The following example is provided to further illustrate the invention.

Example

According to the process according to the invention, waste gas containing 1000 ppm sulfur dioxide was treated under the following conditions:

- reactor: 13 m long, 13 m wide and 10 m high;

- maximum volume flow of waste gas:

000,000 m ³ / h;

- waste gas flow rate range: 50-100% (with steady operation);

- Degree of desulphurisation Z: 90%;

- the waste gas p; density: 1.1 kg / m ³ ;

- absorbance liquid p _n density: 1100 kg / m ³ ;

- circular gas distribution pipes

- D _s diameter: 0.15 m;

- L | distance (typical distance between adjacent gas distribution pipes): 0.15 m; and

- number: 1390 pieces;

- circular holes for gas injection

_Dh diameter: 0.03 m;

- number: 12; and

- P distance (typical distance between adjacent holes): 0.0393 m;

- average distance L _n : 0,2 m;

- maximum flowrate V _max : 24.2 m / s;

S = 0.03; and

- Y pressure: about 0.28 m.

Under these circumstances, desulphurisation has, in our experience, been carried out at a minimal cost, taking into account both construction, installation and operating costs.

The process of the invention may also be carried out using other specific methods without departing from the spirit of the invention or the essential features of the invention. Thus, the embodiments described herein are exemplary in all respects, i.e., not limiting in any respect. The scope of the invention is not primarily defined by the claims, but by the appended claims, and any variation which results in an equivalent solution based on the interpretation and scope of the claims is part of the invention.

Claims (10)

PATENT CLAIMS A process for desulphurizing waste gases containing sulfur dioxide by injecting the waste gases into a stirred volume of mixed absorbent liquid charged to a reactor vessel through a plurality of gas distributor tubes extending vertically downstream of said space divider plate and, at its lower end, in the wall of the tube, has a plurality of laterally circumferential holes for gas injection, wherein said waste gases release sulfur in contact with said absorbent liquid and the desulphurized gases enter an upper space between said partition plate and said fluid level, that the holes for gas injection in each of said gas distribution pipes are arranged in a substantially horizontal row; - in each of said gas distribution pipes, each of the two adjacent holes for gas injection is spaced so that, if each of said two gas injection holes is considered to be a circle having the same area as said hole, said two gas injection adjacent holes are is the distance P between the centers of the hole 1.15 <P / D <6, where D is the diameter of the smaller of the two circles; passing said waste gases at a maximum velocity V _{max for} gas injection EN 221 091 Β1 each of these holes to be filled Y <4.5 S; Y <24 S; - a 0.05 <Y <1.0; and - conditions 0.005 <S <0.06, where Y is the pressure required to desulphurize the given waste gas and S is the quotient of the tensile pressure of said waste gas blown through said V _max at said maximum flow rate and the density of said absorbent liquid; the gas distribution tubes are arranged such that the minimum distance Lj between the two adjacent gas distribution tubes is such that the ratio 1.5 <L, / S <10.0, wherein S is as defined above; and - holes of the gas injection, that is positioned in said gas dispersing pipes each of that L _{n is} an average distance between said absorbing measured by gas injection pause and the liquid level and, for each hole that the gas injection midpoint be valid for 2 <L „/ S <20 where S is as defined above. 2. The method of claim 1, wherein the S values are set to be satisfied Y = 6.5 S; Y <22 S; - a 0.05 <Y <1.0; and the conditions 0.005 <S <0.06, wherein Y and S are as defined in claim 1. The method of claim 1, wherein said minimum distance Lj is set at 0.05-0.6 m and said average distance L _n is set at 0.05-0.9. A process according to claim 1, wherein the amount of said absorbent liquid in said reactor vessel is controlled such that the L _n / S ratio is in the range of 2-20. The method of claim 1, wherein air is injected into said absorbent fluid in an amount such that the L _It / S ratio is in the range of 2 to 20. 6. The method of claim 1, wherein said absorbent fluid is mixed with one or more agitators such that a power of 0.05 to 0.2 kW per 1 m ^{3 of} said absorber fluid is used to operate the agitator. 7. The method of claim 1, wherein said desulphurized gas is flown upstream at an average velocity of 0.5-5 m / s and in an horizontal direction up to an average velocity of 8 m / s. The method of claim 1, wherein only gas distributor pipes having an equivalent diameter of 25-300 mm and an equivalent gas diameter of 3-100 mm are provided in each of them. The method of claim 1, wherein said desulphurized gas in said upper space is introduced through at least one riser into a chamber in the upper portion of said reactor vessel and then discharged from said reactor vessel through an outlet in said chamber. A method according to claim 9, characterized in that said desulphurized waste gas is flown in a horizontal direction in said chamber at an average velocity of up to 10 m / s.